As filed with the Securities and Exchange Commission on October 4, 2012

Securities Act File No. 333-103022

Investment Company Act File No. 811-21295

SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, D.C. 20549

FORM N-1A

REGISTRATION STATEMENT

UNDER

THE SECURITIES ACT OF 1933

¨

Pre-Effective Amendment No.

¨

Post-Effective Amendment No. 235

x

and/or

REGISTRATION STATEMENT

UNDER

THE INVESTMENT COMPANY ACT OF
1940

¨

Amendment No. 236

x

(Check appropriate box or boxes)

JPMORGAN TRUST I

(Exact Name of Registrant Specified in Charter)

270 Park
Avenue

New York, New York, 10017

(Address of Principal Executive Offices)

Registrants Telephone
Number, Including Area Code: (800) 480-4111

Frank J. Nasta, Esq.

J.P. Morgan Investment Management Inc.

270 Park Avenue

New York, NY 10017

(Name and Address of Agent for Service)

With copies
to:

Pamela L. Woodley, Esq.

Jon S. Rand, Esq.

JPMorgan Chase & Co.

Dechert LLP

270 Park Avenue

1095 Avenue of the Americas

New York, NY 10017

New York, NY 10036

It is proposed that this filing will become effective (check appropriate box):

x

immediately upon filing pursuant to paragraph (b)

¨

60 days after filing pursuant to paragraph (a)(1)

¨

75 days after filing pursuant to paragraph (a)(2)

¨

on , 2011 pursuant to paragraph (b).

¨

on , 2011 pursuant to paragraph (a)(1).

¨

on (date) pursuant to paragraph (a)(2).

If
appropriate, check the following box:

¨

The post-effective amendment designates a new effective date for a previously filed post-effective amendment.

EXPLANATORY NOTE

This Post-Effective Amendment No. 235 relates to the following fund:

JPMorgan Tax Aware Income Opportunities Fund

SIGNATURE

Pursuant to the requirements of the Securities Act of 1933, as amended, and the Investment Company Act of 1940, as amended, the Registrant, JPMorgan Trust I, certifies that it meets all the requirements
for the effectiveness of this Registration Statement under Rule 485(b) under the Securities Act of 1933, and has duly caused this Post-Effective Amendment to the Registration Statement to be signed on its behalf by the undersigned, duly
authorized, in the City of New York and State of New York on the 4th day of October, 2012.

JPMORGAN TRUST I

By:

PATRICIA A.
MALESKI*

Patricia A. Maleski

President and Principal Executive Officer

Pursuant to the requirements of the Securities Act of 1933, this registration statement has been signed below by
the following persons in the capacities indicated on October 4, 2012.